Measuring instrument



Ffih 1948. A, J. ROSENBERGER 2,436,451

MEASURING INSTRUMENT Filed March 22, 1945 Patented Feb. 24, 1948 UNITED. sa -rares PAT EN T OFFIC MEASURING INSTRUMENT Albert J Rosenberger,

Republic Flow Meters corporation of Illinois Chicago; 111.; assignor to; Company, Chicago,;lll., a

Application March 22, 1945," Serial No. 584,072 v 6 Claims; (Cl. 137-'153;)

This invention- -relates to measuring- -instru'-' ments andmore particularly toinstruments of the type whichproduce a regulated jpressure in response to variations in acon-dition' to bemeasured Immany instrument applications where instru ments-=are-used either torproduce an indication or -to-control a process-orthe like, it is desirable to be able to change-the range of the instrument. For example measuring instruments which are used to calibrate other instruments or controllers may-be called upon to give indicationsinresponse to wide-variations in conditions to beindicated. Similarly; in the control processes, it is frequently desirable to use the ---same apparatus for 1 slightly 1 different-processes which may require difierent control ranges.

Itis accordingly one of th'e objectsof I the pres-- ent invention toprovide-a measuring-instrument whose-range can be ad usted quickly and easily andwhich provides a high" degree-ofaccuracy throughout its full operation- Another-object is-to provide a measuring instrument which will produce an output pressure variable throughout difierent ranges in response to a given-range of conditions to'be measured.

Still another obje'ct is to provide a measuring instrument-which is readily adjustable to-respond I to difierent'ranges-of conditions to be measured. A- specific obj ectof the invention-is to provide a measuring instrument employing responsive diaphragmsor -the' like in which the effective area of the diaphragms -mayeasilyand quickly be changed.---

The-above and-ptherobjects and advantages of the-invention will be morereadily' apparent from the followingdescriptionwhen-read in 0011- nectionwith the-accompanying drawing, in which the single figure- -is' a diagrammatic view of an instrument embodying the invention.-

The-instrumenty as shown; comprisesa base or support indicated as aplate 10 upon which theseveral instrument parts are mounted. Above the base a hollow housing I l 'is mounted in which- 3, balance beam-l2 is =pivoted=about an axis 13;" lhe -b'eam- 12' may be-pivotally mounted in the musing-1 l' and may be sealed in the housing to Jrevent'escapeof-fiuid therepast in the manner lisclosedand claimed inmy Patent No. 2,299,179. The beam-is urged inone-direction about its pivotal mounting by meansresponsive to the con- H dition to be measured" As shown,.this means comprises a pair of flexible diaphragms I4 and lfifthe diaphragm Mbeing larger than the dia- 5 aphragm. l5ito provide substantiallytwice the effectiveareaw The 'diaphragms are concentrically supportedina housing I Bsecured to the plate l0 and are'connected to move together by a post llwhich-extends through "the plate l0 and is e connectedto the beam I2.

shown; the diaphragms are so arranged-thattheywill-exertan upward force on the beam I2 to urge it clockwise about its pivot.

tionin the flow pipe.

be vented to atmosphere. As shown theconduit I8 is connected through a passage 2| in thehousing l6"to the space above the diaphragm l4 and the conduit I 9'is connected through 'a similar passage 22'to the space below the diaphragm: It:

The space-between the diaphragms Mand 15 communicates through a passage 23 with a valve port z l'formedin a valve housing 25. A rotatable valve plug 26 in the housing can be turned toconnect the port 24'selectively to a passage 2? communicating with the conduit l8-or to a passage 28 communicating with the-conduit l9. In

this way the space between the diaphragms may be selectively connected to either'of the pressure sources.

When the valve plug 26*isturned to the posi- 40 ti'on'sh'own, the-passage I9 is connected to both sides of the diaphragm l5 so-that this diaphragm is ineffective andthe force exerted on the beam I2 tending-to'tilt it clockwise is equal to the area of the diaphragm I ltimes the pressure difference between the sources; If'the valve plug is turned 90 clockwise both sides of the diaphragm M are connected to the conduit l8'sothat diaphragm I4 is inefiective and the force exerted on the beam 12 is-equalto the areaof the diaphragm l5 times the-pressure=diiierence betweenthe sourcea- By In the construction 7 purpose the beam member 33 which valve plug 26.

The beam (2 is adapted to be urged in a counterclockwise direction by a flexible diaphragm 3! supported n the plate l0 and connected to the right end of the beam by a pest 32. The beam will move through a relatively small range in response to the balance of forces exerted by the diaphragms l4, l and 3|.

Movement of the beam, as described, is utilized to produce a regulated pressure and for this carries at its outer end a valve is moved toward and away from an orifice 34 variably to restrict the orifice. The orifice communicates with a passage 35 which is connected through a restriction 33 to a conduit 31 communicating with a source of fluid such as air under pressure. The passage 35 is connected through tubing 38 to the space below the diaphragm 3i and through a pipe 39 to an indicating or control mechanism of any desired type to indicate the condition or toefiect a control operation in response to the condition.

In operation of the instrument as so far described, the diferential pressure acting across either of diaphragms l4 or IE tends to tilt the beam l2 clockwise to restrict the flow of fluid from'the orifice'34. This causes an increase of pressure in the passage 35 which acts on the diaphragm 3| so that it tends to tilt the beam l2 counter-clockwise. With this mechanism a pressure will be created in the passage 35 which is proportional to the clockwise tilting force on the beam 12 so that the beam I2 will be balanced. This pressure can be utilized through the conduit 39 eitherto indicate the condition which causes the pressure differential across diaphragms l4 and I5 or to effect a control operation in response to the condition; It will be seen that the range of pressure produced in the passage 35 will be changed relatively to the range of pressure differentials at the sources according to whether diaphragm [4 or 15 is effective. Therefore, by adjusting the valve 26 to select the desired one of these diaphragms, the range of indication or control produced by the instrument is adjusted.

In addition to the range selection provided by the valve 26 or as a substitute therefor, a second d aphragm 4| may be provided mounted on the base and connected to the left end of the beam l2 to oppose the diaphragm 3|. The space below the diaphragm 4! is connected through a pipe 42 and a three-way valve 43 to the pipe 38. The valve 4 3 may be adjusted to connect the pipe 42 either to pipe 38'or to an atmospheric port 44. c

When the valve 43 connects pipes 38 and 42, both diaphragms 3i and M .are responsive to the pressure in the passage 35. The diaphragm 4! is substantially smaller than the diaphragm 3i and opposes it so that this diaphragm serves to reduce the effective area of the diaphragm 3!.-

Therefore, under these conditions, a greater pressure is required in the passage 35 to produce the same counter-clockwise force on the beam 12 than when the diaphragm 41 is not effective. By turning the valve 43 to vent the space below diaphragm 41 to atmosphere, the efiect of this diaphragm is removed and the full area of diaphragm 3| is effective to exert a counterclockwise force on the beam I2. It will be understood lated fluid pressure, one of vention, reference being had for responsive to the balance of the last named diaphragm means that the diaphragm 4| and its control valve 43 may be used in conjunction with the two diaphragms l4 and I5 to provide additional operating ranges for the instrument or that either of the double diaphragm arrangements might be used without the other where only two ranges of operation are desired.

While one embodiment of the invention has been shown and described in detail, it will be understood that this is illustrative only and is not intended as a definition of the scope of the inthis purpose to the appended claims.

What is claimed is:

1. A measuring instrument comprising a pivoted balance beam, diaphragm means responsive to a condition to be measured to urge the beam in one direction, diaphragm means connected to the beam to urge it in the other direction, means the forces acting on the beam to produce a regulated fluid pressure,

the last named diaphragm means being connected to said means to be responsive to the reguthe diaphragm means including a pair of separate diaphragms, and a valve to equalize the pressure across one of the diaphragms to make it ineffective thereby to change the operating range of the instrument.

2. A measuring instrument comprising a pivoted balance beam, diaphragm means responsive to a condition to be measured to urge the beam in one direction, diaphragm means connected to the beam to urge it in the other direction, means responsive to the balance of the forces acting on the beam to produce a regulated fluid pressure, the last named diaphragm means being connected to said means to be responsive to the regulated fluid pressure, one of the diaphragm means includin a pair of separate diaphragms of different sizes, and valve means for selectively making the diaphragms effective thereby to change the operating range of the instrument,

3. A measuring instrument comprising a pivoted balance beam, diaphragm means responsive to a condition to be measured to urge the beam in one direction, diaphragm means connected to the beam to urge it in the other direction, means responsive to the balance of the forces acting on the beam to produce a regulated fluid pressure, being connected to said means to be responsive to the regulated fluid pressure, one of the diaphragm means including a pair of diaphragms of different sizes so connected to the beam as to oppose each other, and valve means to make the smaller of said pair of diaphragms ineffective.

4. A measuring instrument comprising a balance beam, means responsive to a condition to be measured to urge the beam in one direction, a diaphragm connected to the beam to urge it in the other direction, means responsive to the balance of the forces acting on the beam to produce a regulated fluid pressure, the diaphragm being responsive to the regulated fluid pressure, a second diaphragm smaller than the first named diaphragm connected to the beam to urge it in said one direction, and valve means to connect the second diaphragm selectively to the last named means or to atmosphere.

5. A measuring instrument comprising a balance beam, a pair of mechanically interconnected spaced diaphragms of different sizes connected to the beam to urge it in one direction, means to connect the outer faces of the diaphragms to sources of diiferent pressures, valve means to connect the space between the diaphragms selectively to either of the sources, pressure responsive means to urge the beam in the other direction, and means responsive to the balance of forces on the beam to produce a regulated fluid pressure, the pressure responsive means being connected to the last named means to be responsive to the regulated fluid pressure.

6. In a measuring instrument, a pressure responsive unit comprising a pair of spaced concentric diaphragms of difierent sizes, means mechanically interconnecting the diaphragms to move together, means connecting the outer surfaces of the diaphragms to difierent sources of pressure, and valve means for selectively con- 10 Number necting the space between the diaphragms to either of said sources;

ALBERT J. ROSENBERGER.

REFERENCES CITED The following references are of record in the file of this patent:

. UNITED STATES PATENTS 

